The invention relates to an axial flow pump.
Pumps for applications with small pressure differentials of typically 100 hPA to 150 hPa and comparatively large volume flows, such as blood pumps, for example, are advantageously designed as axial flow pumps. Document WO 96/18358 describes a blood pump of this type having a pipe-shaped pump housing in which a rotor is in each case rotatably supported in a bearing at the ends. The described rotor includes a cylindrical rotor body, with a hub adjacent to it on the inlet side and an end piece adjacent to it on the outlet side, each of which run out into a bearing spigot. Furthermore, a plurality of curved vanes are provided on the rotor body and a permanent magnet is provided in the interior of the rotor body to magnetically drive the rotor. The comparatively large contact area of the hub, rotor body and end piece with the blood and the bearings arranged in the volume flow promote the creation of deposits and thromboses.
Patent specification U.S. Pat. No. 6,527,521 B2 discloses a further development of a blood pump having a pipe-shaped pump housing in which a hollow cylindrical rotor is arranged which is provided with permanent magnets at the periphery. The rotor is chamfered at both ends and the pump housing is tapered at the corresponding points such that the gap between the rotor and the pump housing is kept small. A stator to drive the rotor magnetically and a plurality of permanent magnets to support the rotor magnetically are arranged on the outer surface of the pump housing. A spiral-shaped vane with a constant pitch is formed on the inner surface of the rotor such that the centre of the rotor is kept open.